APPH Ltd.

Page 1

June 21/89 Revision 1 Feb 03 32–40

Engineering Division, Unit 1, Pembroke Court, Chancellor Road, Manor Park, Runcorn,

Cheshire, WA7 1TG, England.

 FAX (+44) 01928 579626 TEL (+44) 01928 532600

SERVICE BULLETIN

32–40

 LANDING GEAR – MAIN GEAR – INSPECT CYLINDER WEB FOR CRACKS

1. PLANNING INFORMATION

A. Effectivity

(1) Units Affected: Main Gear – Port Types: 1863/1 to /8 without strike-off 3

B00A702850A without strike-off 7

B00A702925A without strike-off 5

Main Gear - Starboard Types 1864/1 to /8 without strike-off 3

B00A702851A without strike-off 7

B00A702926A without strike-off 5

(2) Items Affected Cylinder – Port 186316 (pre mod EHM–27)

Cylinder – Starboard 186416 (pre mod EHM–27)

Cylinder – Port 186318 (pre mod 81/05/007)

Cylinder – Starboard 186418 (pre mod 81/05/007

B. Reason

A crack, which has been attributed to fatigue, has been reported originating from the

redundant microswitch hole in the cylinder spigot web.

C. Description

This service bulletin requires an NDT inspection to be made for signs of cracking around

the hole in the cylinder rear spigot web and in the area at the rear edge of the web.

D. Compliance

For Compliance, refer to BAE SYSTEMS Jetstream Service Bulletin 32–A–JA851226.

E. Approval

The contents of this bulletin have been approved under Civil Aviation Authority Design

Approval Number DAI/1033/39.

F. Manpower

Assuming the main gear to be available for inspection, allow 2 manhours to complete the

inspection detailed in this bulletin.

G. Material, cost and availability – Not applicable.

H. Tooling – Not applicable.
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June 21/89 Revision 1 Feb 03 32–40

 LANDING GEAR – MAIN GEAR – INSPECT CYLINDER WEB FOR CRACKS

I. Weight and Balance – Not affected.

J. Electrical Load Data – Not Applicable.

K. References

(1) BAE SYSTEMS Jetstream service bulletin 32–A–JA851226

L. Other Publications Affected

(1) APPH Overhaul Manual 32–10–1 (Formerly BAe Dynamics).

2. ACCOMPLISHMENT INSTRUCTIONS

With the main gear removed from the aircraft and available for inspection proceed as follows:

A. Materials and Equipment (Alternative equivalents can be used)

The following equipment is necessary for the inspection.

(1) Hocking locator UH crack detector.

(2) Non ferrous ‘bolt hole’ probe 2 MHz.

(3) Non ferrous shielded spade 2 MHz.

(4) Standard calibration block, 3 slot.

(5) Inhibisol (solvent) to BS4487.

(6) Epoxy primer to MIL–PRF–23377 Type 1, Class C.

(7) Gloss paint MIL–P–85285 Type 1, FED–STD 595, Colour 16440 or (DTD 5555)

Colour BS381C Code 627 DEF STAN 03–7/1.

(8) Alocrom 1200 to MIL–C–5541 Class 1A (DTD906/4413).

(9) Paint remover, Ardrox 20 to AFS 1426 or plastic abrasive.

B. Prepare cylinder (Fig. 3)

(1) At the first application of this service bulletin blend out the wirelock hole, remove any

corrosion and sharp edges in accordance with Fig. 3. When this action is complete

mark L67 adjacent to the part number using the same method of marking as

previously used.

(2) Remove the paint from the web around hole and edge with paint remover ‘Ardrox

20’ or other approved paint remover. Alternatively, plastic abrasive can be used.

Clean the area using Inhibisol or suitable solvent .
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June 21/89 Revision 1 Feb 03 32–40

 LANDING GEAR – MAIN GEAR – INSPECT CYLINDER WEB FOR CRACKS

C. Set and calibrate test set.

(1) Train and zero equipment on calibration block.

(2) Using the sensitivity control, calibrate test set to give 80% of full scale meter

deflection from 0.019 inch (0.5 mm) slot in standard calibration block. Re–check the

zero.

(3) Connect ‘bolt hole’ probe to lead and test set and set in accordance with the test set

calibration instructions.

(4) Insert ‘bolt hole’ probe into hole in cylinder web and train by gently rocking probe in

hole. Make sure that the train lights operate. Zero the test set with the probe tip

facing inwards toward the leg.

(5) Check for correct training by rocking the probe to illuminate the lift–off light. Make

sure that the meter deflection does not exceed 20% Full Scale Deflection (FSD).

D. Inspect the main gear cylinder web. (Figs. 1 and 2)

(1) Push probe through hole until the end of the probe is flush with the web face. This

will position the probe tip about 0.040 inch (1 mm) from edge of hole.

(2) Carry out a 360 degree scan in this position and at 0.079 inch (2 mm) intervals

throughout the hole.

(3) Connect shielded spade probe to lead and test set, and set up in accordance with

the test set calibration instructions.

(4) Position probe in scan area on inboard face of web and train equipment (ref. Fig.1).

(5) Check for correct training on web face in a similar position.

(6) Position probe on inboard spot face at position X, 0.059 inch (1.5 mm) from edge

of web, and zero the equipment.

(7) Carry out a scan (B) (Fig.1) in both directions from position X to approximately 90

degrees around the hole each way.

(8) Position probe 0.059 inch (1.5 mm) from edge of chamfer and zero equipment.

(9) Maintaining 0.059 inch (1.5 mm) distance from chamfer, carry out a 360 degree scan

(C) around hole (Fig.1).

(10) Place the probe on aft edge of web at position Y, 0.059 inch (1.5 mm) from inboard

face, and zero the equipment (Fig.2).

(11) Maintaining 0.059 inch (1.5 mm) distance from the edge, carry out scan (D) along

the edge of the web (Fig.2).

(12) Repeat the scans detailed in paras (3) to (10) on spot face on outboard face of web.

(13) Cracks up to 0.050 inch (1.27 mm) deep can be blended out. After blending, the

surface finish must be perfectly smooth and free from marks.

(14) Any crack found in excess of 0.05 inch (1.27 mm) deep renders the cylinder

unserviceable. The cylinder must then be replaced before further flight.

(15) Repair small cracks within the limitations of para. 2.D. (13) or repair corrosion in

accordance with Fig.3.
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June 21/89 Revision 1 Feb 03 32–40

(16) Small cracks and corrosion which are blended out must be subjected to full NDT

inspection before applying primer and paint.

E. Reprotect repaired area

(1) Protect any area where the surface finish has been removed using Alocrom 1200

followed by primer and polyurethane paint.

F. Record compliance with this Service Bulletin.

(1) Record compliance with this Service Bulletin in the aircraft log book and in the log

cards for the port and starboard main gear.

(2) Record compliance with this Service Bulletin in the aircraft log book and in the log

cards for the port and starboard main gear.

G. MATERIAL INFORMATION

Not applicable.

4. ISSUING AUTHORITY

Signed..............................................................Date.......22–4–03.....

CHIEF DESIGN ENGINEER – APPH LIMITED
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June 21/89 Revision 1 Feb 03 32–40

 LANDING GEAR – MAIN GEAR – INSPECT CYLINDER WEB FOR CRACKS

SPOT FACE

CHAMFER

SCAN PATH ‘C’

WEB

TYPICAL DEFECT

POSITION ‘X’

SCAN PATH ‘B’

Aft Web Face (Inboard Face is Similar)

Figure 1
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June 21/89 Revision 1 Feb 03 32–40

POSITION Y

TYPICAL DEFECT

SCAN PATH ‘D’

WEB

Aft Edge of Web

Figure 2
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June 21/89 Revision 1 Feb 03 32–40

Removal of Corrosion

Figure 3